As a swift action, you can imbue your weapons with a fraction of your power. For 1 round, your weapons deal +1 damage and are treated as magic for the purpose of overcoming damage reduction. For every five caster levels you possess, this bonus increases by +1, to a maximum of +5 at 20th level.

does this mean that if i Have 20 caster levels at all, I get the max bonus? If i am sorc 10/bard 10 (dont ask why) would i get the full bonus to damage? or would i have to have 20th level caster level?